Preheat oven to 350ºF and line 12-cup muffin pan or spray with oil; set aside.
In a mixing bowl combine almond flour, cornstarch, baking soda and salt; set aside.
In large bowl whisk together oil, honey, milk, vanilla and lemon juice. Add in eggs – whisk until combined.
Add dry ingredients to bowl of wet, and as mixture comes together, fold in blackberries.
Evenly distribute batter into 12-cup muffin pan (about 3/4 way full). Top with more blackberries and almond slices as a crunchy topping.
Bake muffins for 18-22 minutes, or until inserted toothpick comes out clean.
Allow muffins to cool in pan for 5 minutes, then transfer to cooling rack.